668 research outputs found
Two Universality Properties Associated with the Monkey Model of Zipf's Law
The distribution of word probabilities in the monkey model of Zipf's law is
associated with two universality properties: (1) the power law exponent
converges strongly to as the alphabet size increases and the letter
probabilities are specified as the spacings from a random division of the unit
interval for any distribution with a bounded density function on ; and
(2), on a logarithmic scale the version of the model with a finite word length
cutoff and unequal letter probabilities is approximately normally distributed
in the part of the distribution away from the tails. The first property is
proved using a remarkably general limit theorem for the logarithm of sample
spacings from Shao and Hahn, and the second property follows from Anscombe's
central limit theorem for a random number of i.i.d. random variables. The
finite word length model leads to a hybrid Zipf-lognormal mixture distribution
closely related to work in other areas.Comment: 14 pages, 3 figure
Emergence of Zipf's Law in the Evolution of Communication
Zipf's law seems to be ubiquitous in human languages and appears to be a
universal property of complex communicating systems. Following the early
proposal made by Zipf concerning the presence of a tension between the efforts
of speaker and hearer in a communication system, we introduce evolution by
means of a variational approach to the problem based on Kullback's Minimum
Discrimination of Information Principle. Therefore, using a formalism fully
embedded in the framework of information theory, we demonstrate that Zipf's law
is the only expected outcome of an evolving, communicative system under a
rigorous definition of the communicative tension described by Zipf.Comment: 7 pages, 2 figure
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